The aforementioned transcoding technique is essential when copying a digital stream recorded on a hard disk (HD), to an optical disc or a memory card. The transcoding technique is employed in various recording devices in areas of consumer product industries.
In transcoding, a digital stream that is compression-coded by MPEG2-TS (Transport Stream), MPEG2-PS (Program Stream), or the like needs to be returned to a decompressed form first. This requires real-time processing. The real-time processing referred to here is a process that takes a processing time equal to a playback time of the digital stream. For example, transcoding of a digital stream corresponding to two-hour video requires real-time processing of two-hours.